Steam generator



Dec- 14, 1943 J. P. BAD-ENHAUSEN l2,336,833

STEAM VGENERATOR Filedl Feb. 1Q, 1942 :e sheets-shed 1 f r 16- J7 i4 65W 29 142s .70 f E fv\ I." Z0 'il J Qc |31 y 14 f4 f? ilf 3 v l 3f l Mentor; JrcP/llg'psdenuwe@ IL 5T ww De 14, 1943- I J. P. BADENHAUSEN i 2,336,833 .STEAM GENERATOR n Filed Feb. 19, '1942' 2 sheets-seet-z IH 2. si: o., 2

j grwmsh Patented Dec. 14, 1943 UNETED TES PATENT OFEIQE 3 Claims.

This invention relates to steam generators, and more particularly to a steam generator which is adapted for the absorption of heat from waste heat gases, and for auxiliary absorption of heat from burning fuel.

In the waste heat boilers which have heretofore been available, particularly for use with open hearth steel furnaces, a very large heating surface has been required in the steam generating unit because of the relatively low temperature, of the order of l,0) of the waste heat gas from the open hearth furnace. This large heating surface required an expenditure greatly in excess of that ordinarily justied, particularly when considered from the viewpoint of the quantity of steam generated in the waste 'heat boiler. Various attempts have heretofore been made to utilize the large heating surface of waste heat boilers to increase the steam output but many difficulties have been encountered. No wholly satisfactory provisions have heretofore been made for using auxiliary fuel with a waste heat boiler, and for utilizing the burning of auxiliary fuel for heat absorption by the large heat absorbing surface of the waste heat boiler. In some instances, attempts have been made to mix gases of combustion from an auxiliary furnace with the waste heat gases in the waste heat boiler. The gases from the auxiliary furnace were of such high temperature that the metallic particles entrained in the waste heat gases were rendered plastic. The plastic particles froze on the heating surfaces and blanketed the same so that steam generation could not be properly effected.

In accordance with the present invention, a steam generator is provided which is particularly adapted for the absorption of heat from waste heat gases from open hearth furnaces, with which auxiliary fuel may be employed, and which is also suitable for operation wholly with the auxiliary fuel at such times as waste heat gases from the open hearth furnaces are not available. 'The necessity for using other steam generators in the plant to supply the steam demand is thus eliminated.

it is the principal object of the present invention to provide a steam generator suitable for heat absorption from waste heat gases and from gases of combustion of auxiliary fuel.

lt is a further object of the present invention to provide a steam generator which is particularly adapted for use with open hearth steel furnaces.

It is a further object of the present invention to provide a waste heat steam generator for operation at higher pressures than those heretofore employed.

It is a further object of the present invention to provide a steam generator which is for alternative operation as desired with waste heat gases and auxiliary fuel.

It is a further object of the present invention to provide a steam generator for waste heat steam generation which is suitable for independent operation, if desired, with auxiliary fuel.

Other objects of the invention will be apparent from the annexed specification and claims.

The nature and characteristic features of the invention will be more readily understood from the following description, taken in connection with the accompanying drawings forming part hereof, in which:

Figure l is a vertical central sectional View through a preferred embodiment of steam generator in accordance with the present invention, taken approximately on the line I-l of Fig. 2;

Fig. 2 is a horizontal section taken approximately on the line 2-2 of Fig. l; and

Fig. 3 is a fragmentary sectional View taken approximately on the line 3 3 of Fig. 1.

It will, `of course, be understood that the description and drawings herein are illustrative merely, and that various modifications and changes may be made in the structure disclosed without departing from the spirit of the invention.

Referring more particularly to the drawings, the steam generator, in accordance with the present invention, is suitably enclosed and includes a vertical front Wall l0, vertical side walls Il and l2 having rear extensions Ila and |2a,

` a top wall lli having a front section Illa, an intermediate section Mb and a rear section Mc, and a floor l5 having a front section l5a, an intermediate section I5b and a rear section IEC. The front section I da of the top wall M is provided with a burner l5 for introducing pulverized coal, oil, gas or any desired fuel together with air supplied by an air duct l'l from a forced draft fan (not shown).

An upper transverse steam and water drum 20 is provided at the rear portion of the intermediate top wall section Mb, and spaced therebelow and near the intermediate fioor section |5b, a transverse lower water drum 2l is provided. A lower front wall header 22 is provided near the bottom of the front wall l0, and is connected to the lower water drum 2l by a bank of tubes 23. An upper front wall header 24 is provided at the junction of the front wall lll and the front top wall section 14a, the lower Water header 22 and the upper header 2d being connected by a bank of steam generating tubes 25 which line the front wall it. The upper front wall header 2 is connected by a bank of tubes 25 which extend substantially horizontally along the lower side of the ront top wall section ida and then upwardly along the intermediate top wall section Mb and into the steam and water drum 20. Thel tubes 26 of the bank of tubes are preferably shaped so as not to interfere with the burner I6.

A lower side wall header 21 is provided in each of the side walls II and I'2, and spaced upwardly from the front iloor section Ia. The drum 2| is connected to each of the headers 21 by tubes 32. An upper side wall header 28 is provided in each of the side walls |I and I2 at the upper ends thereof. The lower side wall headers 21 are respectively connected to the upper side wall headers 28 by banks of steam generating tubes 29 which line the front side wall sections of the side walls II and I2. The upper side wall headers 28 are connected by banks of tubes 29 to the steam and water drum for the delivery of steam thereto. Y

A baille 3D is provided, spaced rearwardly from the front wall I0, and extends downwardly from the top wall I4, the lower end being terminated to permit gas flow therearound as hereinafter morefully pointed out. v

A bank of tubes 3| is provided which extends from the water drum 2| first forwardly and upwardly, as at 3Ia, and then upwardly in the baille 30 toward the top wall I4, and then into the steam and water drum 2i).

A combustion chamber is thus provided enclosed within the front wall |I), the front top wall section I 4a, the front sections of the side walls ,II and I2, and the baille 3B. The fuel and air for combustion in the co-mbustion chamber 35 are supplied through the burner I5. The space 36 below the combustion chamber 35 and below the tubes 23 provides for the collection of ash and solid lresidues resulting from the use of certain fuels. At the outlet of the combustion chamber 35 alternate tubes SIb of the bank of tubes 3|, see Figs. 1 and 3, may be offset forwardly to permit the passage of gas from the combustion chamber 35 therethrough. The tubes of the bank of tubes 3| act as a screen, and aid in the collect.. ing of ash and the like in the space 36.

A gas duct 48 for the delivery of waste heat gasesfrom an open hearth steel furnace or other suitable source is provided, and preferably extends through the floor l5 at the intermediate floor section I 5b and from one side wall I to the other side wall I2. The gas duc-t 48 has a rear duct wall 4| extending to the lower water drum 2|, and a front duct wall 42 parallel thereto extend- -ing upwardly to the bank of tubes 23. A damper 43 is provided for controlling the ilow of the waste heat gases through the duct 48 and into :the steam generator.

' An inclined baille 44 is provided which extends upwardly and rearwardly from the upper extremn ity of the'front duct wall 42and a vertical baille 45 extends upwardly from the baille 44, but is terminated below the intermediate top wall section |4b to permit the flowV of gases thereover.

An upward pass 46 for the gases from the combustion chamber 35 is thus provided between the downwardly extending baille 30 and the upwardly extending baille 45, the gases being guided and directed into the upward pass by the inclined baille 44. A bank of tubes 41 is also preferably provided in the upward pass 46 for steam generation and further cooling of the gases passing from the combustion chamber 35, and the tubes of this bank 41 extend from the water drum 2l across the discharge from the gas duct 40, then upwardly inthe upward pass 45, and to the steam and water drum 20. The rearmost row of tubes of the bank of tubes 41 preferably extend along and aid in supporting the baille 45.

An upwardly disposed baille 48 is provided with tubes 49v along the forward face thereof upwardly from the water drum 2| to a location spaced from the top wall section |4b to permit the passage of gases over the top edge thereof. The baille 48 provides, with the baille 45, an upward pass 58 for waste heat gases introduced through the duct 48 and guided into the upward pass 5!) by the baille 44. The forward side of the upward pass 58 preferably is provided with a row of tubes 5I which extend forwardly and upwardly from the Vwater drum 2|, upwardly along the rear face of the baille 45, and into the steam and Water drum 28.

It will be noted that the tubes 23, the tubes 3|, the tubes of the bank of tubes 41, and the row of tubes 5| extend across the entrance to the upward pass 5|) and serve as a screen for the entering waste heat gases.

It will be noted that at the upper end of the upward pass 46 and the upper end of the upward pass 55 a mixing space' 52 is provided within which the gases from the furnace chamber 35 and the waste heat gases will intermingle and mix prior to their exit from the mixing space 52. The gases from the upward pass 46 and from the upward pass 50 are preferably controlled by control of the burner IB and the damper 43 so that the gases upon absorption of heat therefrom and delivery to the mixing space 52 are at aD- proximately the same temperature. In any event the temperature of the gases delivered from the upward pass 48 must not be at an excessive temperature.

To the rear of the baille 48 a vertical downwardly extending baille 53 is provided, this baille 53V extending downwardly from the steam and water drum 20 and being terminated at a location spaced from the water drum 2| for the passage of gases around the lower edge thereof. The baille 53 provides, with the baille 48, a downward pass 54 for the mixed gases. A bank of steam generating tubes 55 is disposed within the pass 54 and the tubes of the bank of tubes 55 extend from the water drum 2| to the upper steam and water drum 2U. The forward row of tubes of the bank of tubes 55 is disposed along the baille 48 for aiding in supporting the baille 48, and the rear row of tubes of the bank of tubes 55 is disposed along the baille 53 for aiding in supporting the baille 53.

An upwardly extending wall 56 is provided to the rear of the baille 53, and extends from the Vterminated below the top wall I4 to permit the front of the rear iloor section I5c toward the front of the rear top wall sec-tion I4. The wall 55 is ilow of gases thereover. An upward pass 51 for the gases is thus provided between the baille 53 and the wall 56.

A bank of tubes 58 is provided vin the upward pass 51 and between the wall 56, and the baille 53, the tubes 58 being connected between the water drum 2| and the steam and water drum 28. The forward row of tubes of the bank of tubes 58 extends along the baille 53 for aiding in supporting the baille 53 and the rear row of tubes of the bank of tubes 58 extends along the wall 56 for cooling the same.

In the space between the wall 56 and the rear wall an economizer 6I is preferably disposed for the downward passage ofthe gases. The economizer 6I is provided with a feed water inlet 82, and is connected by suitable tubes 63 to the steam and water drum 20.

- An induced draft fan 65 may be connected to the gas outlet of the econornizer 6I for the withdrawal of gases from the steamgenerator and the delivery of the same to a stack (not shown). The induced draft fan 65 is of sufficient capacity to handle the waste heat gases from the open hearth steel furnace, and also the gases from the burning of the auxiliary fuel.

The steam generator illustrated is suitable for operation at a pressure of 600 to 700 pounds per square inch, but is not intended to be restricted to operation at these pressures.

A superheater 653 is provided and is connected to the steam space of the steam and water drum 2d. The superheater 5d preferably includes a section of tubes 6l disposed at the upper end or" the upward pass 53 and in the gas mixing space 52, and a section of tubes 68 extending downwardly in the upward pass e5, the tubes of the superheater 66 being connected to a superheated steam delivery header ld. The superheater 65 is suitable for providing from 100 to 150 degrees of superheat in the steam, but is not intended to be limited to this range.

The Inode of operation of the steam generator will now be pointed out.

The fuel and air introduced from the burner l5 are burned at the desired rate in the combustion chamber 25, and the burning gases pass downwardly within the combustion chamber 35. A substantial portion of the heat generated by the combustion in the combustion chamber 35 is absorbed as radiant heat by the banks of tubes lining the chamber 35. The burning gases pass from the combustion chamber 35 through the screen provided by the tubes of the bank of tubes El and then pass upwardly through the upward pass it where a further portion of the heat in the combustion gases is given up to the tubes oi the bank of tubes lill for further steam generation, and the section SS of the superheater 65 for superheating the steam from the drum Ztl. rEhe heat absorbing surfaces which are effective in the combustion chamber 35 and in the upward pass d'5 reduce the temperature of the gases prior to their entry into the mixing space 52 to an extent suoli that ne metallic particles carried in the waste heat gases are not rendered plastic. The waste heat gases enter through the duct lill, under the control of the damper 3, and pass upwardly through the upward pass 5i! to the mixing space 52 where they mix with the gases from the combustion chamber 35. The mixed gases then pass downwardly through the downward pass 5d, and then upwardly through the upward pass 5l where further quantities of heat are given up. The gases than pass downwardly through the economizer 6I where further quantities of heat are given up, and are withdrawn by the induced draftrfan $5 and delivered to the stack (not shown).

In the event that it is not desired to use the waste heat gases from the open hearth steel furnace, or other source, the damper i3 is closed and the gases from the combustion chamber 35 follow the path heretofore pointed out without any mixing of waste heat gases therewith.

In the event that the steam demand is low and does not require the use of the combustion chamber 35, the waste heat gases pass upwardly through the upward pass 5S, downwardly through the downward pass 5d, upwardly through the upward pass 5l, and downwardly through the economizer El, and through the induced drait fan 55 in the same manner as before but lesser quantities of gas pass through than if the combustion chamber 35 were in operation.

It will be noted that the disposition of the superheater sections 61 and G8 provide for superheating of the steam for each of the alternate modes of operation.

I claim:

1. In a steam generator, a front wall, a top wall, and side walls, a steam receiving drum, banks oi steam generating tubes connected to said drum for cooling said walls, a first baiile spaced from said front wall for enclosing with said walls a combustion chamber, a secend baille to the rear of said rst bailie for providing a ver tical combustion gas pass for the gases from said combustion chamber, a waste heat gas duct for admitting gas to the rear of said second baffle, banks of steam generating tubes connected to said drum and having portions extending across the outlet of said duct and within said comu bustion gas pass, additional bailes for providing additional gas passes for said combustion gases and said waste heat gases, and additional banks of steam generating tubes in said passes connected to said drum.

2. In a steam generator, a front wall, a top wall, and side walls, a transverse steam and water drum, banks of steam generating tubes connected to said drum for cooling said walls, a vertical baille extending downwardly from said top wall and spaced from said front wall for enclosing with said walls a combustion chamber, fuel sup ply means in said top wall for supplying fuel for combustion in said combustion chamber, a second vertical baille to the rear of said irst baille for providing an upward combustion gas pass for the combustion gases from said combustion chamber, a waste heat gas duct to the rear of said combustion chamber for admitting gas to the rear of said second baille, banks of vertical steam generating tubes connected to said drum and Vhaving portions extending across the outlet of said duct, additional vertical baiiies to the rear of said other baiiies providing additional gas passes for said combustion gases and said waste heat gases, and additional banks of vertical steam generating tubes in said additional passes connected to said drum.

3. In a steam generator, a front wall, a top wall, and side walls, a transverse steam and water drum, banks of steam generating tubes connected to said drumrior cooling said walls, ya first vertical baile spaced from said front wall for enclosing with said walls a combustion chamber, a second vertical baffle to the rear of said rst baii'ie for providing a combustion gas pass for the gases from said combustion chamber, a waste heat gas duct for admitting gas to the rear of said second baille, banks of vertical steam generating tubes connected to said drum and having portions extending across the outlet of said duct, additional Vertical baflies to the rear of said other baiiies for providingr additional gas passes for said combustion gases and said 4waste heat gases, additional Vertical banks of steam generating tubes in said additional passes connected to said drum, and a superheater connected to said drum and having a portion vertically disposed in the path of said waste heat gases and a portion vertically disposed in the combustion gas pass.

JOHN PHILLIPS BADENHAUSEN. 

